I have only had the one device for right ear about two weeks. Still trying to get the right ear parts to fit comfortable so this review is not my final one for this product. Since I have about 80-90 percent hearing loss of the right ear, this product maybe my answer to at least some hearing gain, but only time will tell. From what I have learned so far is, that I may have to employ the larger tube ie. power kit to really improve performance. Right now I am still experimenting with the default setup as received. I will edit, update this review when I am more comfortable with the device